CA1310300C - Plasma treatment method and apparatus with multiple tanks - Google Patents
Plasma treatment method and apparatus with multiple tanksInfo
- Publication number
- CA1310300C CA1310300C CA000512326A CA512326A CA1310300C CA 1310300 C CA1310300 C CA 1310300C CA 000512326 A CA000512326 A CA 000512326A CA 512326 A CA512326 A CA 512326A CA 1310300 C CA1310300 C CA 1310300C
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- Canada
- Prior art keywords
- plasma
- tanks
- evacuating
- openable
- communicating
- Prior art date
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
- B29C59/14—Surface shaping of articles, e.g. embossing; Apparatus therefor by plasma treatment
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Physical Or Chemical Processes And Apparatus (AREA)
- Plasma Technology (AREA)
Abstract
PLASMA TREATMENT METHOD
AND APPARATUS WITH MULTIPLE TANKS
ABSTRACT
A method and apparatus for plasma treating workpieces such as resin moldings with a plurality of tanks each connected to a plasma generator by a lead-in pipe diverging to a plurality of shower pipes, each supplying a tank. A valve is provided in each shower pipe so that workpieces in one tank are being treated while workpieces are prepared for treatment in the other tank. A vacuum pump and booster are also connected to each pump by communicating pipes and valves.
AND APPARATUS WITH MULTIPLE TANKS
ABSTRACT
A method and apparatus for plasma treating workpieces such as resin moldings with a plurality of tanks each connected to a plasma generator by a lead-in pipe diverging to a plurality of shower pipes, each supplying a tank. A valve is provided in each shower pipe so that workpieces in one tank are being treated while workpieces are prepared for treatment in the other tank. A vacuum pump and booster are also connected to each pump by communicating pipes and valves.
Description
1 - 1 3 1 ~'J
1 The present invention relates to a plasma treatment apparatus for activating treatment on the surfaces of synthetic resin moldings.
BRIEF DESCRIPTION OF T~E DRAWINGS
.
FIG. 1 is a diagram for explaining the plasma treatment operation carried out through a first system in an apparatus according to the present invention.
FIG. 2 is a diagram for explaining the plasma treatment operation carried out through a second system in the apparatus according to the present invention.
FIG. 3 is a diagram for explaining the pre-operation in the first systemO
~5 FIG. 4 is a diagram for explaining the pre-operation in the second system.
FIG. 5 is a partially broken side view of a conventional plasma treatment apparatus.
Conventionally, moldings of nonpolar polymers such as polyethyLene, polypropylene, or the like/ adhere poorly to coating materials, and therefore are surface activated be~ore coating. For surface activationl various methods of treatment, for example, ultraviolet ray irradiation, corona discharge, primer application, and so on have been used. All these methods, however still have disadvantages in that adhesion to a coatiny material is still not sufficient, the cost for treatment is relatively high, and so on. Because of these $~-, ~"
1 ,,, 1 disadvantages, plasma treatment is increasingly used. Figure 5 shows one con~entional plasma treating apparatus.
Shower pipes 52 for a plasma generator 51 are provided in a plasma treatment tank 55 which accommodates resin moldings to be coated. ~ raw material gas and high frequency waves are fed respectively from a bomb 53 and a high frequency generator 54 into plasma generator 51 to produce a plasma gas. The plasma gas is fed into plasma treatment tank 55 through shower pipes 52.
In order to evacuate plasma treatment tank 55, the tank 55 is connected to a communicating pipe 56 at its one end. A mechanical booster 58 is connected with the communicating pipe 56 at its other end, and a communicating pipe 59 iS attached at its one end to the booster 58~ A rotary pump 60 is attached to the communicating pipe 59 at its other end, so that tank 55 ls evacuated when the mechanical booster 58 and the rotary pump 60 are operated.
In the thus arranged plasma treatment apparatus, generally, a number of resin moldings can be accommodated in the plasma treatment tank 55 so that it is possible to manufacture a number of plasma-treated moldings during each treatmentO
Accordingly, the apparatus has high productivity from the point of throughput.
Recently, however, as demands for such moldings have become diverse, var;ous kinds of plasma-treated products must be manufactured in small quantitles. Because plasma treatment is , , ~
. .
, 1 performed in a vacuum, moldings to be treated must be put into and taken out of the space where the plasma treatment is performed. Thus, every time moldings are put into and taken out of the tank, the vacuum is lost and must be recovered.
In manufacturing small quantities of diverse kinds of products, the number of products per lot is reduced and the number of the lots is increased, so that it is necessary to increase the number of cycles. If the number of the cycles of plasma treatment is increased, the treatment time per product is substantially increased. This is unacceptable in practice and the number of treatment cycles must be decreased if the conventional plasma treatment apparatus is to be used as it is. If a few products are manufactured per cycle of plasma treatment by using a plasma treatment tank having a large capacity, there is a further problem that the manufacturing cost rises.
An object of the present invention is to provide a plasma treatment apparatu~ which can effectively and efficiently treat small quantities of and diverse kinds of resin moldings.
In order to solve the problem~ described above, according to the present invention, the plasma treatment apparatus includes a plasma gas leading-in pipe diverging into a plurality of shower pipes with a plasma generator connected thereto.
The shower pipes are respectively connected with a plurality of plasma treatment tanks each having a vacuum device. Each of the sho~er pipes is provided with an openable/closable fluid valve.
- 3a -1 In one of its aspects the invention resides in a plasma treatment apparatus comprising a single plasma generating means; a plurality of plasma treatment tanks each for receiving workpieces to be treated; first communicating means for selectively communicating said plasma treatment tanks to said plasma generating means so as to introduce plasma to selected tanks; a pluralit~ of first evacuating means each for evacuating an associated one of said tanks to produce a vacuum therein; a single second evacuating means for evacuating said tanks to produce a vacuum therein; and second communicating means for selectively communicating said plasma treatment tanks to their respective associated first evacuating means directly and via said second evacuating means so as to produce a Yacuum therein and for selectively communicating said plasma treatment tanks to said second evacuating means so as to produce a vacuum therein, said second communicating means including third communicating means for selectively connecting said first evacuating means to said second evacuating means, each of said plasma treatment tanks further including leak valve means adapted to return said plasma treatment tanks to atmospheric pressure.
In a further aspect the invention resides in a method of plasma treatment of workpieces in at least two plasma tanks with plasma generated in a single plasma generating means, said plasma tanks being selectively communicated to said plasma generating means by first openable/closable valve means, said plasma tanks being selectively communicated by second openable/closable valve means to associated first evacuating means for producing a vacuum in said plasma tanks and to a single second evacuating means for producing a vacuum in said plasma D
- 3b -1 tanks~ each of said plasma tanks having leak valve means for introducing air therein, the steps comprising switching said first openable/closable valve means to communicate said plasma generating means to selected ones of said plasma tanks where a vacuum is produced by second evacuating means, to thereby introduce plasma into said selected plasma tanks and treat workpiece in said selected plasma tanks while preparing workpieces for treatment in the other tanks; closing said leak valve means of the ]o other tanks and switching said second openable/closable valve means to communicate the other tanks to said first evacuating means; producing a vacuum in the other tanks by said first evacuating means; switching said first openable/closable valve means to separate said selected plasma tanks from said plasma generating means to stop treatment of workpieces in said selected plasma tanks, switching said second openable/closable valve means to separate said selected plasma tanks from said second evacuating means; opening said leak valve means of said selected plasma tanks, switching said second openable/closable valve means to separate the other plasma tanks from the associated first evacuating means and communicate the other plasma tanks to said second evacuating means; producing a vacuum in the other plasma tanks by said second evacuating means while replacing workpieces in said selected plasma tanks; and s~tching said first openable/closable valve means to communicate the other plasma tank where a vacuum is produced to said plasma generating means to introduce plasma into said other plasma tanks and treat workpieces in the other plasma tanks.
-D
1 ~ecause the plasma leading-in pipe is connected with one plasma generator and diverges into a plurality of shower pipes, plasma treatment can be carried out for only the plasma treatment tank/tanks communicated with the shower pipe/pipes in which the openable/closable valve/valves are opened, while the remainder of the plasma treatment tanks can be prepared for plasma treatment.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to Figs. 1 through 5, an embodiment of the plasma treatment apparatus according to the present invention will be described hereunder. In this embodiment, the plasma treatment apparatus includes a plurality of plasma treatment tanks each having a small capacity. Since the structure per se of each component such as the plasma treatment tanks, etc., is the same or similar to that of the above-mentioned conventional apparatus, the apparatus is srhematically illustrated in Figs. 1 through 4.
First and a second systems A and B each include shower pipes 3 diverging from the same plasma gas leading-in pipe 2. A plasma treatment tank 5 is connect~d with the shower pipe 3, and a vacuum device 4 communicates with each treatment tank 5 through communicating pipes 6, 7 and 8, etc. Therefore, the apparatus will be described hereunder with the two systems distinguished from each other by adding symbols a and b to the reference numerals of the systems A and B
respectively.
A single plasma generator 1 is fed with a raw gaseous material such as an oxygen gas from a bomb 12 through a feedins pipe 14 having an openable/closable valve 17 disposed midway in the feeding pipe 14 and supplied with high frequency energy from a high frequency oscillator 15 through a waveguide 16.
1 3 1 030~
1 The plasma generator 1 is preferably constituted by a plasma generating pipe made o~ a quartz and a Tesla coil for inducing plasma by generating a spark in synchronism with the high frequency oscillator 15 when the high frequency oscillator is started.
The plasma gas generated in the plasma generator 1 is led into a single plasma gas leading-in pipe 2 and then can be fed into plasma treatment tanks 5a and 5b through two shower pipes 3a and 3b diverging from plasma gas leading-in pipe 2. An openable/closable valve 13a for fluid is provided midway in shower pipe 3a and, similarly, an openable/closable valve 13b is provided midway in shower pipe 3b. The openable/closable valves 13a and 13b are used for feeding the pla~na gas r gen2rated in the plasma generator 1 into the plasma trea~ment tanks 5a and 5b respectively.
Accordingly, when plasma gas is being fed into plasma treatment tank 5a, the openable/closable valve 13a is in an open state while the openable/
closable valve 13b is in a closed state as shown in Fig. 1. When the plasma gas is being fed into the plas~a treatment tank 5b, on the contrary, the openable/closable valve 13b is in an open state whil_ the openable/closable valve 13a is in a closed state as shown in Fig. 2.
The plasma treatment tank 5a is constituted by a pressure-withstanding vessel having a leaking valve 18a. The shower pipe 3a is connected with plasma treatment tank 5a to which a communicating pipe 6a ~s further attached to exhaust gas inside the tank Sa through a vacuum device which will ~e described below.
131~)3CO
1 Similarly, plasma treatment tank 5b is a vessel having a leaking valve 18b and the shower pipe 3b and a communicating pipe 6b attached to tank 5b.
A stand on which resin moldings arè to be put or attached is fixedly or movably attached to the inside of each of the plasma treatment tanks 5a and 5b. The moldings may be brought into the plasma treatment tanks 5a and Sb through openable/closable caps provided on the ront surfaces of the plasma treatment tanks 5a and 5b, respectively.
Midway in communicating pipe 6a is provided an openable~closable valve 9a. A mechanical booster 4c is also coupled to pipe 6a. Communicating pipe 6b is also provided with an openable/closable valve 9b and integrated with the communicating pipe 6a so as to communicate with the same mechanicai booster 4c. The structure of the mechanical booster 4c per se is conventional and a Roots booster is generally used. The mechanical booster 4c is connected with a rotary pump 4a through a communicating pipe 8a ~
provided with an openable/closable valve lla.
Similarly, mechanical booster 4c is connected also with another rotary pump 4b through a communicating pipe 8b, partly commonly with the communicating pipe 8a. Midway in communicating pipe 8b is also - provided an openable/closable valve llb.
As to the four openable/closable valves 9a, 9b, lla, and llb provided in the respective communicating pipes 6a, 6b, 8ar and 8b, the openable/closable valves 9b and llb are closed when the openable/closable valves 9a and lla are being opened as shown in Fig. 1, while the openable/
closable valves 9b and llb are opened when the 1 openable/closable valves 9a and lla are being closed as shown in Fig. 2.
The openable/closable valves 9a and llb, and the openable/closable valves 9b and lla are never both opened or closed at the same time, respectively. If they are operated to open or close at the same time, such effects as described later cannot be obtained.
A communicating pipe 7a is also connec~ed at its opposite ends with the communicating pipes 6a and 8a. Communicating pipe 7a has an openable/
~losable valve lOa which is opened when openable/
closable valves 9b and llb are opened as shown in Fig. 2.
Similarly, a communicating pipe 7b is connected at its opposite ends with the communicating pipes 6b and 8b, and pipe 7b is provided midway with openable/closable valve lOb.
As shown in Fig. 1, when the openable/
closable valves ~b and llb are closed and the openable/closable valves 9a and lla are opened, the openable/closable valve lOb is opened.
Thus, rotary pumps 4a and 4b are communicating with plasma treatment tanks 5a and 5b through parallel paths, one causing the communi-cating pipes 6a and 6b, the mechanical booster 4c, and the communicating pipes 8a and 8b to communicate with each other, and the other rotary pump being constituted by the other communicating pipes 7a and 7b.
The opening/closing operations of the openable/closable valves are automatically performed by conventional control devices (not shown).
The plasma treatment apparatus of the present embodiment having the above mentioned structure operates as follows.
~ "v~
8 1 3 1 ~
1 After placement of resin moldings in plasma treatment tank 5a has been finished, the rotary pump 4a is operated with the openable/closable valve lOa opened while the leaking valve 18a, openable/closable valves 13a, 9a and lla are closed as shown in Fig. 3.
Next, after the inside o~ the plasmatreatment tank 5a has reached a predetermined vacuum state, the mechanical booster 4c and the rotary pump 4a are operated with openable/closable valve lOa closed and the openable/closable valves 9a and lla are opened as shown in the first system A of Fig.
1. Thus, the inside of the plasma treatment tank 5a is in the vacuum state required for plasma treatment.
~ The openable/closable valve 13a of the shower pipe 3a is opened, the plasma oscillator 15 is started, and at the same time the Tesla coil is energized. Then, the openable/closa~le valve 17 of 2Q the bomb 12 is opened so that oxygen gas is fed into the plasma generator 1 to cause the plasma generator 1 to ~enerate a plasma gas.
When the plasma gas has been generated, the Tesla coil is deenergized. The plasma gas is led into the plasma treatment tank 5a and the resin moldings in the plasma treatment tank 5a are activated by plasma-treatment with openable/closable valves 17, 13a, 9a and lla opened as shown in the first system A of Fig. 1.
Upon completion of plasma treatment in the plasma treatment tank 5a oxygen gas flow from bomb 12 is stopped, and plasma generator 1, booster pump 4c, the rotary pump 4a, etc., are tem?orarily stopped to switch the operation to the second system B. Then, openable/closable valve 13a, 3a, and lla 1 are closed and leaking valve 18a is opened to return the inside of the plasma treatment tank 5a to an atmospheric state. Finally, the plasma-treated resin moldings are taken out of the tank, and the cycle of plasma treatment in the first system A is terminated.
After the placement of ~he resin moldings in the plasma treatment tank Sa in the irst system A
has been completed, placement of workpieces in plasma treatment tank 5b of second system B is carried out.
A~ter this is done, as shown in Fig. 4, the openable/closable valve 10b is opened with leaking valve 18b closed, and rotary pump 4b is operatedO
Because the above-mentioned operations are carried out in para].lel with plasma treatm2nt in the plasma treatment tan~ 5a in the first system A, openable/closable valves 13b, 9b, and llb have been already closed.
The schedule is preferably arranged such that when the preparation for the plasma treatment has proceeded to this point, the inside of plas~a treatment tank 5b is in a predetermined vacuum state and the plasma tre~tment in the first system A is terminated. Now, opelable/closable valve 10b is closed and openable/
closable valves 9b and llb are opened successively in second system B shown in Fig. 2. The mechanical booster 4c and the rotary pump 4b are also operated together~ Thus, the inside of plasma treatment tank 5b s evacuated as required for plasma treatment.
Openable/closable valve 13b o shower pipe 3b is opened. The plasma oscillator lS is started and at the same time the Tesla coil is energized.
Then, the openable/closable valve 17 of the bomb 12 is opened so that an oxygen gas is ed into the ~ 3 ~ 030~
1 plasma generator 1 to cause the plasma generator 1 to generate a plasma gas. Then, the plasma gas is led into plasma treatment tank Sb and the resin moldings in the plasma treatment tank 5b are activated.
Upon completion of the plasma txeatment in the plasma treatment tank 5b, the oxygen gas flow is stopped and plasma generator 1, booster pump 4c, rotary pump 4b, etc., are temporarily stopped to switch operation back in the first system A. Then, openable/closable valves 13b, 9b, and llb are closed and leaking valve 18b is opened to return the inside of plasma treatment tank 5b into an atmospheric state. Finally, the plasma-treated resin moldings are taken out of the tank, and the cycle of plasma treatment in the second system B is terminated.
As described above, a plurality of plasma treatment tanks are used in the plasma treatment apparatus of the present embodiment, so that the ~0 apparatus is applicable to a so-called "Toyota manufacturing system" in which a small quantity of various kinds of resin moldings are plasma-treated.
Further, not only can the operations of the first system A and the second system B be efficiently performed, but the first system A can be prepared during the operation of the second system B
and the second system B can be prepared during the operation of the first system Af so that each plasma treatment cycle can be shortened to remarkably improve productivity.
Conventionally, a plasma treatment tank having large capacity has been required to be operated even when a small quantity of resin moldings are treated. According to the present invention, on the contrary, if a plurality of plasma 11 1 ~ 1 0300 1 treatment tanks of various capacities are arranged in the plasma treatment apparatus, a proper combination of plasma treatment tanks can be matched to the quantity of resin moldings to be treated, and hence operation cost can be reduced.
Further, the plasma oscillator can be used without reducing the output thereof and almost without stopping the operation of the same.
The present invention is not limited to the arrangement as described above but can be carried out, for example, in the modified mode as follows.
The vacuum device 4 may have any suitable structure and the plasma treatment tank 5 can be evacuated by using only either the mechanical booster or the rotary pump. Further, a vacuum device 4 may be provided for each plasma treatment tank S.
According to the present invention, remarkable effects can be obtained. Preparation for plasma treatment in one plasma treatment tank can be carried out during plasma treatment in other plasma treatment tank/tanks, so that the plasma treatment cycle can be made fast without reducing the rate of operation of the plasma generator.
Further, because a plurality of plasma treatment tanks are provided, any one or ones of the plas~a treatment tanks can be selectively used in accordance with the number of moldings to be trea ed, plasma treatment can be carried out with a reduced output of the plasma generator, and the plas~a oscillator can be used without reducing the output thereof and almost without stopping the operation of the same, so that the manufacturing cost can be reduced.
1 The present invention relates to a plasma treatment apparatus for activating treatment on the surfaces of synthetic resin moldings.
BRIEF DESCRIPTION OF T~E DRAWINGS
.
FIG. 1 is a diagram for explaining the plasma treatment operation carried out through a first system in an apparatus according to the present invention.
FIG. 2 is a diagram for explaining the plasma treatment operation carried out through a second system in the apparatus according to the present invention.
FIG. 3 is a diagram for explaining the pre-operation in the first systemO
~5 FIG. 4 is a diagram for explaining the pre-operation in the second system.
FIG. 5 is a partially broken side view of a conventional plasma treatment apparatus.
Conventionally, moldings of nonpolar polymers such as polyethyLene, polypropylene, or the like/ adhere poorly to coating materials, and therefore are surface activated be~ore coating. For surface activationl various methods of treatment, for example, ultraviolet ray irradiation, corona discharge, primer application, and so on have been used. All these methods, however still have disadvantages in that adhesion to a coatiny material is still not sufficient, the cost for treatment is relatively high, and so on. Because of these $~-, ~"
1 ,,, 1 disadvantages, plasma treatment is increasingly used. Figure 5 shows one con~entional plasma treating apparatus.
Shower pipes 52 for a plasma generator 51 are provided in a plasma treatment tank 55 which accommodates resin moldings to be coated. ~ raw material gas and high frequency waves are fed respectively from a bomb 53 and a high frequency generator 54 into plasma generator 51 to produce a plasma gas. The plasma gas is fed into plasma treatment tank 55 through shower pipes 52.
In order to evacuate plasma treatment tank 55, the tank 55 is connected to a communicating pipe 56 at its one end. A mechanical booster 58 is connected with the communicating pipe 56 at its other end, and a communicating pipe 59 iS attached at its one end to the booster 58~ A rotary pump 60 is attached to the communicating pipe 59 at its other end, so that tank 55 ls evacuated when the mechanical booster 58 and the rotary pump 60 are operated.
In the thus arranged plasma treatment apparatus, generally, a number of resin moldings can be accommodated in the plasma treatment tank 55 so that it is possible to manufacture a number of plasma-treated moldings during each treatmentO
Accordingly, the apparatus has high productivity from the point of throughput.
Recently, however, as demands for such moldings have become diverse, var;ous kinds of plasma-treated products must be manufactured in small quantitles. Because plasma treatment is , , ~
. .
, 1 performed in a vacuum, moldings to be treated must be put into and taken out of the space where the plasma treatment is performed. Thus, every time moldings are put into and taken out of the tank, the vacuum is lost and must be recovered.
In manufacturing small quantities of diverse kinds of products, the number of products per lot is reduced and the number of the lots is increased, so that it is necessary to increase the number of cycles. If the number of the cycles of plasma treatment is increased, the treatment time per product is substantially increased. This is unacceptable in practice and the number of treatment cycles must be decreased if the conventional plasma treatment apparatus is to be used as it is. If a few products are manufactured per cycle of plasma treatment by using a plasma treatment tank having a large capacity, there is a further problem that the manufacturing cost rises.
An object of the present invention is to provide a plasma treatment apparatu~ which can effectively and efficiently treat small quantities of and diverse kinds of resin moldings.
In order to solve the problem~ described above, according to the present invention, the plasma treatment apparatus includes a plasma gas leading-in pipe diverging into a plurality of shower pipes with a plasma generator connected thereto.
The shower pipes are respectively connected with a plurality of plasma treatment tanks each having a vacuum device. Each of the sho~er pipes is provided with an openable/closable fluid valve.
- 3a -1 In one of its aspects the invention resides in a plasma treatment apparatus comprising a single plasma generating means; a plurality of plasma treatment tanks each for receiving workpieces to be treated; first communicating means for selectively communicating said plasma treatment tanks to said plasma generating means so as to introduce plasma to selected tanks; a pluralit~ of first evacuating means each for evacuating an associated one of said tanks to produce a vacuum therein; a single second evacuating means for evacuating said tanks to produce a vacuum therein; and second communicating means for selectively communicating said plasma treatment tanks to their respective associated first evacuating means directly and via said second evacuating means so as to produce a Yacuum therein and for selectively communicating said plasma treatment tanks to said second evacuating means so as to produce a vacuum therein, said second communicating means including third communicating means for selectively connecting said first evacuating means to said second evacuating means, each of said plasma treatment tanks further including leak valve means adapted to return said plasma treatment tanks to atmospheric pressure.
In a further aspect the invention resides in a method of plasma treatment of workpieces in at least two plasma tanks with plasma generated in a single plasma generating means, said plasma tanks being selectively communicated to said plasma generating means by first openable/closable valve means, said plasma tanks being selectively communicated by second openable/closable valve means to associated first evacuating means for producing a vacuum in said plasma tanks and to a single second evacuating means for producing a vacuum in said plasma D
- 3b -1 tanks~ each of said plasma tanks having leak valve means for introducing air therein, the steps comprising switching said first openable/closable valve means to communicate said plasma generating means to selected ones of said plasma tanks where a vacuum is produced by second evacuating means, to thereby introduce plasma into said selected plasma tanks and treat workpiece in said selected plasma tanks while preparing workpieces for treatment in the other tanks; closing said leak valve means of the ]o other tanks and switching said second openable/closable valve means to communicate the other tanks to said first evacuating means; producing a vacuum in the other tanks by said first evacuating means; switching said first openable/closable valve means to separate said selected plasma tanks from said plasma generating means to stop treatment of workpieces in said selected plasma tanks, switching said second openable/closable valve means to separate said selected plasma tanks from said second evacuating means; opening said leak valve means of said selected plasma tanks, switching said second openable/closable valve means to separate the other plasma tanks from the associated first evacuating means and communicate the other plasma tanks to said second evacuating means; producing a vacuum in the other plasma tanks by said second evacuating means while replacing workpieces in said selected plasma tanks; and s~tching said first openable/closable valve means to communicate the other plasma tank where a vacuum is produced to said plasma generating means to introduce plasma into said other plasma tanks and treat workpieces in the other plasma tanks.
-D
1 ~ecause the plasma leading-in pipe is connected with one plasma generator and diverges into a plurality of shower pipes, plasma treatment can be carried out for only the plasma treatment tank/tanks communicated with the shower pipe/pipes in which the openable/closable valve/valves are opened, while the remainder of the plasma treatment tanks can be prepared for plasma treatment.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to Figs. 1 through 5, an embodiment of the plasma treatment apparatus according to the present invention will be described hereunder. In this embodiment, the plasma treatment apparatus includes a plurality of plasma treatment tanks each having a small capacity. Since the structure per se of each component such as the plasma treatment tanks, etc., is the same or similar to that of the above-mentioned conventional apparatus, the apparatus is srhematically illustrated in Figs. 1 through 4.
First and a second systems A and B each include shower pipes 3 diverging from the same plasma gas leading-in pipe 2. A plasma treatment tank 5 is connect~d with the shower pipe 3, and a vacuum device 4 communicates with each treatment tank 5 through communicating pipes 6, 7 and 8, etc. Therefore, the apparatus will be described hereunder with the two systems distinguished from each other by adding symbols a and b to the reference numerals of the systems A and B
respectively.
A single plasma generator 1 is fed with a raw gaseous material such as an oxygen gas from a bomb 12 through a feedins pipe 14 having an openable/closable valve 17 disposed midway in the feeding pipe 14 and supplied with high frequency energy from a high frequency oscillator 15 through a waveguide 16.
1 3 1 030~
1 The plasma generator 1 is preferably constituted by a plasma generating pipe made o~ a quartz and a Tesla coil for inducing plasma by generating a spark in synchronism with the high frequency oscillator 15 when the high frequency oscillator is started.
The plasma gas generated in the plasma generator 1 is led into a single plasma gas leading-in pipe 2 and then can be fed into plasma treatment tanks 5a and 5b through two shower pipes 3a and 3b diverging from plasma gas leading-in pipe 2. An openable/closable valve 13a for fluid is provided midway in shower pipe 3a and, similarly, an openable/closable valve 13b is provided midway in shower pipe 3b. The openable/closable valves 13a and 13b are used for feeding the pla~na gas r gen2rated in the plasma generator 1 into the plasma trea~ment tanks 5a and 5b respectively.
Accordingly, when plasma gas is being fed into plasma treatment tank 5a, the openable/closable valve 13a is in an open state while the openable/
closable valve 13b is in a closed state as shown in Fig. 1. When the plasma gas is being fed into the plas~a treatment tank 5b, on the contrary, the openable/closable valve 13b is in an open state whil_ the openable/closable valve 13a is in a closed state as shown in Fig. 2.
The plasma treatment tank 5a is constituted by a pressure-withstanding vessel having a leaking valve 18a. The shower pipe 3a is connected with plasma treatment tank 5a to which a communicating pipe 6a ~s further attached to exhaust gas inside the tank Sa through a vacuum device which will ~e described below.
131~)3CO
1 Similarly, plasma treatment tank 5b is a vessel having a leaking valve 18b and the shower pipe 3b and a communicating pipe 6b attached to tank 5b.
A stand on which resin moldings arè to be put or attached is fixedly or movably attached to the inside of each of the plasma treatment tanks 5a and 5b. The moldings may be brought into the plasma treatment tanks 5a and Sb through openable/closable caps provided on the ront surfaces of the plasma treatment tanks 5a and 5b, respectively.
Midway in communicating pipe 6a is provided an openable~closable valve 9a. A mechanical booster 4c is also coupled to pipe 6a. Communicating pipe 6b is also provided with an openable/closable valve 9b and integrated with the communicating pipe 6a so as to communicate with the same mechanicai booster 4c. The structure of the mechanical booster 4c per se is conventional and a Roots booster is generally used. The mechanical booster 4c is connected with a rotary pump 4a through a communicating pipe 8a ~
provided with an openable/closable valve lla.
Similarly, mechanical booster 4c is connected also with another rotary pump 4b through a communicating pipe 8b, partly commonly with the communicating pipe 8a. Midway in communicating pipe 8b is also - provided an openable/closable valve llb.
As to the four openable/closable valves 9a, 9b, lla, and llb provided in the respective communicating pipes 6a, 6b, 8ar and 8b, the openable/closable valves 9b and llb are closed when the openable/closable valves 9a and lla are being opened as shown in Fig. 1, while the openable/
closable valves 9b and llb are opened when the 1 openable/closable valves 9a and lla are being closed as shown in Fig. 2.
The openable/closable valves 9a and llb, and the openable/closable valves 9b and lla are never both opened or closed at the same time, respectively. If they are operated to open or close at the same time, such effects as described later cannot be obtained.
A communicating pipe 7a is also connec~ed at its opposite ends with the communicating pipes 6a and 8a. Communicating pipe 7a has an openable/
~losable valve lOa which is opened when openable/
closable valves 9b and llb are opened as shown in Fig. 2.
Similarly, a communicating pipe 7b is connected at its opposite ends with the communicating pipes 6b and 8b, and pipe 7b is provided midway with openable/closable valve lOb.
As shown in Fig. 1, when the openable/
closable valves ~b and llb are closed and the openable/closable valves 9a and lla are opened, the openable/closable valve lOb is opened.
Thus, rotary pumps 4a and 4b are communicating with plasma treatment tanks 5a and 5b through parallel paths, one causing the communi-cating pipes 6a and 6b, the mechanical booster 4c, and the communicating pipes 8a and 8b to communicate with each other, and the other rotary pump being constituted by the other communicating pipes 7a and 7b.
The opening/closing operations of the openable/closable valves are automatically performed by conventional control devices (not shown).
The plasma treatment apparatus of the present embodiment having the above mentioned structure operates as follows.
~ "v~
8 1 3 1 ~
1 After placement of resin moldings in plasma treatment tank 5a has been finished, the rotary pump 4a is operated with the openable/closable valve lOa opened while the leaking valve 18a, openable/closable valves 13a, 9a and lla are closed as shown in Fig. 3.
Next, after the inside o~ the plasmatreatment tank 5a has reached a predetermined vacuum state, the mechanical booster 4c and the rotary pump 4a are operated with openable/closable valve lOa closed and the openable/closable valves 9a and lla are opened as shown in the first system A of Fig.
1. Thus, the inside of the plasma treatment tank 5a is in the vacuum state required for plasma treatment.
~ The openable/closable valve 13a of the shower pipe 3a is opened, the plasma oscillator 15 is started, and at the same time the Tesla coil is energized. Then, the openable/closa~le valve 17 of 2Q the bomb 12 is opened so that oxygen gas is fed into the plasma generator 1 to cause the plasma generator 1 to ~enerate a plasma gas.
When the plasma gas has been generated, the Tesla coil is deenergized. The plasma gas is led into the plasma treatment tank 5a and the resin moldings in the plasma treatment tank 5a are activated by plasma-treatment with openable/closable valves 17, 13a, 9a and lla opened as shown in the first system A of Fig. 1.
Upon completion of plasma treatment in the plasma treatment tank 5a oxygen gas flow from bomb 12 is stopped, and plasma generator 1, booster pump 4c, the rotary pump 4a, etc., are tem?orarily stopped to switch the operation to the second system B. Then, openable/closable valve 13a, 3a, and lla 1 are closed and leaking valve 18a is opened to return the inside of the plasma treatment tank 5a to an atmospheric state. Finally, the plasma-treated resin moldings are taken out of the tank, and the cycle of plasma treatment in the first system A is terminated.
After the placement of ~he resin moldings in the plasma treatment tank Sa in the irst system A
has been completed, placement of workpieces in plasma treatment tank 5b of second system B is carried out.
A~ter this is done, as shown in Fig. 4, the openable/closable valve 10b is opened with leaking valve 18b closed, and rotary pump 4b is operatedO
Because the above-mentioned operations are carried out in para].lel with plasma treatm2nt in the plasma treatment tan~ 5a in the first system A, openable/closable valves 13b, 9b, and llb have been already closed.
The schedule is preferably arranged such that when the preparation for the plasma treatment has proceeded to this point, the inside of plas~a treatment tank 5b is in a predetermined vacuum state and the plasma tre~tment in the first system A is terminated. Now, opelable/closable valve 10b is closed and openable/
closable valves 9b and llb are opened successively in second system B shown in Fig. 2. The mechanical booster 4c and the rotary pump 4b are also operated together~ Thus, the inside of plasma treatment tank 5b s evacuated as required for plasma treatment.
Openable/closable valve 13b o shower pipe 3b is opened. The plasma oscillator lS is started and at the same time the Tesla coil is energized.
Then, the openable/closable valve 17 of the bomb 12 is opened so that an oxygen gas is ed into the ~ 3 ~ 030~
1 plasma generator 1 to cause the plasma generator 1 to generate a plasma gas. Then, the plasma gas is led into plasma treatment tank Sb and the resin moldings in the plasma treatment tank 5b are activated.
Upon completion of the plasma txeatment in the plasma treatment tank 5b, the oxygen gas flow is stopped and plasma generator 1, booster pump 4c, rotary pump 4b, etc., are temporarily stopped to switch operation back in the first system A. Then, openable/closable valves 13b, 9b, and llb are closed and leaking valve 18b is opened to return the inside of plasma treatment tank 5b into an atmospheric state. Finally, the plasma-treated resin moldings are taken out of the tank, and the cycle of plasma treatment in the second system B is terminated.
As described above, a plurality of plasma treatment tanks are used in the plasma treatment apparatus of the present embodiment, so that the ~0 apparatus is applicable to a so-called "Toyota manufacturing system" in which a small quantity of various kinds of resin moldings are plasma-treated.
Further, not only can the operations of the first system A and the second system B be efficiently performed, but the first system A can be prepared during the operation of the second system B
and the second system B can be prepared during the operation of the first system Af so that each plasma treatment cycle can be shortened to remarkably improve productivity.
Conventionally, a plasma treatment tank having large capacity has been required to be operated even when a small quantity of resin moldings are treated. According to the present invention, on the contrary, if a plurality of plasma 11 1 ~ 1 0300 1 treatment tanks of various capacities are arranged in the plasma treatment apparatus, a proper combination of plasma treatment tanks can be matched to the quantity of resin moldings to be treated, and hence operation cost can be reduced.
Further, the plasma oscillator can be used without reducing the output thereof and almost without stopping the operation of the same.
The present invention is not limited to the arrangement as described above but can be carried out, for example, in the modified mode as follows.
The vacuum device 4 may have any suitable structure and the plasma treatment tank 5 can be evacuated by using only either the mechanical booster or the rotary pump. Further, a vacuum device 4 may be provided for each plasma treatment tank S.
According to the present invention, remarkable effects can be obtained. Preparation for plasma treatment in one plasma treatment tank can be carried out during plasma treatment in other plasma treatment tank/tanks, so that the plasma treatment cycle can be made fast without reducing the rate of operation of the plasma generator.
Further, because a plurality of plasma treatment tanks are provided, any one or ones of the plas~a treatment tanks can be selectively used in accordance with the number of moldings to be trea ed, plasma treatment can be carried out with a reduced output of the plasma generator, and the plas~a oscillator can be used without reducing the output thereof and almost without stopping the operation of the same, so that the manufacturing cost can be reduced.
Claims (7)
1. A plasma treatment apparatus comprising:
a single plasma generating means;
a plurality of plasma treatment tanks each for receiving workpieces to be treated;
first communicating means for selectively communicating said plasma treatment tanks to said plasma generating means so as to introduce plasma to selected tanks;
a plurality of first evacuating means each for evacuating an associated one of said tanks to produce a vacuum therein;
a single second evacuating means for evacuating said tanks to produce a vacuum therein; and second communicating means for selectively communicating said plasma treatment tanks to their respective associated first evacuating means directly and via said second evacuating means so as to produce a vacuum therein and for selectively communicating said plasma treatment tanks to said second evacuating means so as to produce a vacuum therein; said second communicating means including third communicating means for selectively connecting said first evacuating means to said second evacuating means, each of said plasma treatment tanks further including leak valve means adapted to return said plasma treatment tanks to atmospheric pressure.
a single plasma generating means;
a plurality of plasma treatment tanks each for receiving workpieces to be treated;
first communicating means for selectively communicating said plasma treatment tanks to said plasma generating means so as to introduce plasma to selected tanks;
a plurality of first evacuating means each for evacuating an associated one of said tanks to produce a vacuum therein;
a single second evacuating means for evacuating said tanks to produce a vacuum therein; and second communicating means for selectively communicating said plasma treatment tanks to their respective associated first evacuating means directly and via said second evacuating means so as to produce a vacuum therein and for selectively communicating said plasma treatment tanks to said second evacuating means so as to produce a vacuum therein; said second communicating means including third communicating means for selectively connecting said first evacuating means to said second evacuating means, each of said plasma treatment tanks further including leak valve means adapted to return said plasma treatment tanks to atmospheric pressure.
2. The plasma treatment apparatus of claim 1, wherein said first evacuating means comprises a rotary pump.
3. The plasma treatment apparatus of claim 1,wherein said second evacuating means comprises a booster pump.
4. The plasma treatment apparatus of claim 1, wherein said first communicating means comprises a lead-in pipe connected to said plasma generating means and having a plurality of shower pipes diverging therefrom, each shower pipe connecting to one of said tanks, and an openable/closable valve in each of said shower pipes for controlling flow of plasma into the associated plasma tanks.
5. The plasma treatment apparatus of Claim 1,wherein said second communicating means includes a first set of communicating pipes each connecting a tank to an associated first evacuating means, a second set of communicating pipes each connecting a tank to said second evacuating means and an openable/closable valve in each of said communicating pipes.
6. The plasma treatment apparatus of claim 1,wherein said second communicating means includes a first set of communicating pipes each connecting a tank to an associated first evacuating means, a second set of communicating pipes each connecting a tank to said second evacuating means, a third set of pipes each connecting an associated one of said first evacuating means to said second evacuating means and an openable/closable valve in each communicating pipe.
7. A method of plasma treatment of workpieces in at least two plasma tanks with plasma generated in a single plasma generating means, said plasma tanks being selectively communicated to said plasma generating means by first Claim 7 cont'd...
openable/closable valve means, said plasma tanks being selectively communicated by second openable/closable valve means to associated first evacuating means for producing a vacuum in said plasma tanks and to a single second evacuating means for producing a vacuum in said plasma tanks, each of said plasma tanks having leak valve means for introducing air therein, the steps comprising:
switching said first openable/closable valve means to communicate said plasma generating means to selected ones of said plasma tanks where a vacuum is produced by second evacuating means, to thereby introduce plasma into said selected plasma tanks and treat workpiece in said selected plasma tanks while preparing workpieces for treatment in the other tanks;
closing said leak valve means of the other tanks and switching said second openable/closable valve means to communicate the other tanks to said first evacuating means;
producing a vacuum in the other tanks by said first evacuating means;
switching said first openable/closable valve means to separate said selected plasma tanks from said plasma generating means to stop treatment of workpieces in said selected plasma tanks, switching said second openable/closable valve means to separate said selected plasma tanks from said second evacuating means; opening said leak valve means of said selected plasma tanks, switching said second openable/closable valve means to separate the other plasma tanks from the associated first evacuating means and communicate the other plasma tanks to said second evacuating means;
Claim 7 cont'd...
producing a vacuum in the other plasma tanks by said second evacuating means while replacing workpieces in said selected plasma tanks; and switching said first openable/closable valve means to communicate the other plasma tank where a vacuum is produced to said plasma generating means to introduce plasma into said other plasma tanks and treat workpieces in the other plasma tanks.
openable/closable valve means, said plasma tanks being selectively communicated by second openable/closable valve means to associated first evacuating means for producing a vacuum in said plasma tanks and to a single second evacuating means for producing a vacuum in said plasma tanks, each of said plasma tanks having leak valve means for introducing air therein, the steps comprising:
switching said first openable/closable valve means to communicate said plasma generating means to selected ones of said plasma tanks where a vacuum is produced by second evacuating means, to thereby introduce plasma into said selected plasma tanks and treat workpiece in said selected plasma tanks while preparing workpieces for treatment in the other tanks;
closing said leak valve means of the other tanks and switching said second openable/closable valve means to communicate the other tanks to said first evacuating means;
producing a vacuum in the other tanks by said first evacuating means;
switching said first openable/closable valve means to separate said selected plasma tanks from said plasma generating means to stop treatment of workpieces in said selected plasma tanks, switching said second openable/closable valve means to separate said selected plasma tanks from said second evacuating means; opening said leak valve means of said selected plasma tanks, switching said second openable/closable valve means to separate the other plasma tanks from the associated first evacuating means and communicate the other plasma tanks to said second evacuating means;
Claim 7 cont'd...
producing a vacuum in the other plasma tanks by said second evacuating means while replacing workpieces in said selected plasma tanks; and switching said first openable/closable valve means to communicate the other plasma tank where a vacuum is produced to said plasma generating means to introduce plasma into said other plasma tanks and treat workpieces in the other plasma tanks.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13735085A JPS61296038A (en) | 1985-06-24 | 1985-06-24 | Apparatus for plasma treatment |
| JP137350/85 | 1985-06-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1310300C true CA1310300C (en) | 1992-11-17 |
Family
ID=15196592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000512326A Expired - Fee Related CA1310300C (en) | 1985-06-24 | 1986-06-24 | Plasma treatment method and apparatus with multiple tanks |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS61296038A (en) |
| CA (1) | CA1310300C (en) |
| DE (1) | DE3620934A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01308436A (en) * | 1987-10-29 | 1989-12-13 | Nishikawa Kasei Kk | Plasma treatment apparatus |
| JPH03119432U (en) * | 1990-03-16 | 1991-12-10 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4192706A (en) * | 1975-01-22 | 1980-03-11 | Tokyo Shibaura Electric Co., Ltd. | Gas-etching device |
-
1985
- 1985-06-24 JP JP13735085A patent/JPS61296038A/en active Pending
-
1986
- 1986-06-23 DE DE19863620934 patent/DE3620934A1/en not_active Ceased
- 1986-06-24 CA CA000512326A patent/CA1310300C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DE3620934A1 (en) | 1987-01-02 |
| JPS61296038A (en) | 1986-12-26 |
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